Whales are highly evolved marine mammals. The simple, direct answer to the question of whether they have eyelashes is no; whales do not possess the keratinized hairs commonly known as eyelashes that are characteristic of land mammals. This absence is a function of evolutionary adaptation to the ocean environment.
The Definitive Answer and Alternative Hairs
Specialized hairs that grow from the eyelid margin, known as true eyelashes, are absent in all cetaceans. Like the rest of the body hair found on most mammals, the whale lineage has significantly reduced this covering for a streamlined shape. Despite lacking eyelashes and a coat of fur, whales are not entirely hairless.
Whales possess rudimentary hairs or hair follicles, often referred to as vibrissae or sensory hairs. In baleen whales, such as the humpback, these hairs are found on the head, specifically on the chin, jawline, and along the upper rostrum. Humpback whales house these sensory hairs within golf ball-sized bumps called tubercles, with a single hair growing from the center of each.
These vibrissae are structurally different from protective eyelashes, being stiffer and having a dense supply of nerves at their base. Functionally, these sensory hairs act as mechanoreceptors, helping the whale detect subtle changes in water pressure and current. This aids in navigation or locating dense patches of prey. Some species, like toothed whales, lose most of these hairs shortly after birth, retaining only the richly innervated follicles beneath the skin.
The Function of Hair in the Marine Environment
The aquatic environment makes the primary functions of terrestrial eyelashes unnecessary. On land, eyelashes serve to filter airborne debris and wick away sweat or rain, preventing them from running into the eye. In the water, dust and wind are non-existent, and the surrounding fluid negates the need for a mechanism to shed moisture.
Hair creates drag, and evolution favors a smooth, hydrodynamic body shape for efficient movement through water. Instead of relying on hair for protection, whales have specialized ocular structures to maintain eye health. The eyes of cetaceans are protected by glands that secrete an oily, gelatinous substance.
This oily material forms a protective film over the cornea and conjunctiva, lubricating the eye and helping to flush out foreign bodies and protect against ocean salinity. This specialized tear substitute differs chemically from terrestrial mammal tears and negates the need for any hair-based defense.
The reduction of hair, including eyelashes, is a clear example of how cetaceans have adapted their mammalian blueprint to thrive in the marine world. Their streamlined bodies and sensory vibrissae reflect a successful evolutionary trade-off, prioritizing hydrodynamics and tactile sensing over the protective hair seen on land.